The invention relates to a device for introducing a catheter into a body cavity, particularly for introducing an in-dwelling catheter into the subarachnoid space to perform continuous spinal anesthesia.
In continuous spinal anesthesia (CSA), when a catheter is introduced into the subarachnoid space (spinal space), the dura delimiting this space is pierced. These dura punctures frequently result in postspinal pain (post dura puncture headache (PDPH)). Such postspinal headaches are caused by an outflow of liquor cerebrospinalis from the subarachnoid space after removal of the puncture needle and introduction of the catheter which has a smaller diameter than the puncture hole generated in the dura.
A known device for introducing a catheter into the subarachnoid space according to U.S. Pat. No. 5,232,442 comprises a catheter having an elongated needle arranged therein. The needle extends along the complete length of the catheter and protrudes out of both ends of the catheter. The (distal) patient end of the needle is provided with a non-cutting tip. First, an insertion cannula is advanced into the epidural space. Subsequently, an auxiliary tube is moved through the insertion cannula and is set against the dural wall without cutting into it. The catheter accommodating the needle is advanced through the auxiliary tube. The tip of the needle pierces the dural wall and together with the catheter generates a hole corresponding to the outer diameter of the catheter. In this manner, the catheter is advanced into the subarachnoid space without undesired escape of liquor. Then, the needle is withdrawn from the catheter, and the catheter can be connected to a syringe for administering an anesthetic. In the above known device, the needle which--is flexible but must have relatively large stiffness--extends along the complete length of the catheter. Thus, the catheter together with the needle accommodated therein has a considerable stiffness, which impairs the handling of the catheter.
It is an object of the invention to provide a device for introducing a catheter which allows for easier handling of the catheter.